Custom onDraw() method not called

user_384185 0
Viewed 47226
<LinearLayout android:id="@+id/svLL" android:orientation="horizontal"
    android:layout_width="fill_parent" android:layout_height="fill_parent">
    <ScrollView android:id="@+id/sv"
        android:layout_width="wrap_content" android:layout_height="wrap_content"
        xmlns:android="http://schemas.android.com/apk/res/android">
        <!--
            <TextView android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/scrollbar_2_text" />
        -->
        <com.mypackage.MyDrawableView
            android:layout_width="fill_parent" android:layout_height="wrap_content" />
    </ScrollView>
</LinearLayout>

public class MyDrawableView extends View {

    Context thisContext;

    public MyDrawableView(Context context, AttributeSet attr) {
        super(context);
        thisContext = context;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        final Paint paint = new Paint();
        paint.setColor(Color.BLUE);
        paint.setTextSize(12);
        canvas.drawText("Blah blah", 0, 100, paint);
    }
}

public class MyActivity extends Activity {
    // Your member variable declaration here
    // Called when the activity is first created.
    @Override
    public void onCreate(Bundle savedInstanceState) {
        // Your code here super.onCreate(savedInstanceState);
        setContentView(R.layout.xmllayout);
        LinearLayout svll = (LinearLayout) findViewById(R.id.svLL);
        svll.setLayoutParams(new LinearLayout.LayoutParams(300, 300));
    }

}

I am putting a breakpoint, but breakpoint is never hit inside onDraw() method, what's wrong ?

drawing android
9 Answers

Probably

setMinimumHeight(width);
setMinimumWidth(height);

in constructor are not set or onMeasure() is not overriden.

user_29141400

Here is one more reason that your view might not be appearing. If you are creating your custom ViewGroup with subviews, remember to add the subviews to your ViewGroup.

In your ViewGroup constructor call

addView(mySubView);

Also remember to measure and layout your subviews in onLayout()

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    mySubview.measure(...);
    mySubview.layout(...);
}
user_36818800
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